When is the greatest period of risk for mastitis?

Greatest Period of Risk for Mastitis

The greatest period of risk for lactational mastitis is within the first 3 months postpartum, with the highest incidence occurring in the first 4 weeks after delivery. 1, 2

Timing of Peak Risk

• The first 3 months postpartum represent the critical window, with approximately 10% of breastfeeding women in the United States developing mastitis during this period 1
• The first 4 weeks postpartum show the highest incidence rates when analyzed by breastfeeding weeks 2
• The pooled incidence rate from 0-25 weeks postpartum is 11.1 episodes per 1,000 breastfeeding weeks, but this rate is not evenly distributed—it concentrates heavily in the early postpartum period 3, 2

Distribution Beyond the Early Period

While the risk is highest early, mastitis can occur throughout the breastfeeding period:

• Two-thirds of mastitis episodes occur in the first 3 months, but one-third occur after 6 months postpartum 4
• Nearly one-quarter of cases occur after one year of breastfeeding, demonstrating that risk persists throughout lactation 4
• The overall prevalence across the entire lactation period ranges from 2.5% to 20% depending on the population studied 3

Clinical Context and Mechanism

The concentration of risk in the early postpartum period relates to several factors:

• Establishment of lactation creates vulnerability through engorgement, milk stasis, and learning proper breastfeeding technique 1
• Nipple damage in the first month increases the adjusted risk ratio for mastitis to 2.07 (95% CI = 1.17-3.66), and nipple trauma is the most strongly associated risk factor 5, 2
• Overstimulation of milk production and tissue trauma from aggressive breast massage or excessive pumping in the early weeks contribute to inflammation 1

Important Caveats

• Antepartum mastitis is rare but can occur, typically in the third trimester, and requires early recognition to prevent abscess formation 6
• Recurrent mastitis affects 8.5% of women, with multiple episodes possible throughout the lactation period 5
• The condition represents a spectrum from inflammation to true infection, with most cases being inflammatory rather than infectious in nature 1